It is assumed that the the REA-5 armor was based on designs by Riff from the Dimension of Rain, since Hereti-Corp stole the designs for his Mark 19 robot in the Sluggy Prime dimension. REA-5 is the only unit of personel in 4U City that is not required to be drugged (except for the executives), which leads to the Resistance planting new members into REA 5.